Suspension design for the co-located PZT micro-actuator

ABSTRACT

A micro-actuator that reduces suspension tongue stiffness and a method of manufacturing the micro-actuator are disclosed. In one embodiment, the micro-actuator has a base piece with two arms extending from the base piece. The electric contact pads for the arms are situated on the exterior of the arms at the end opposite the base piece. In one embodiment, the electric contact pads are electrically coupled to the same connection plate that the magnetic read/write head is coupled to, reducing the number of connection traces.

BACKGROUND INFORMATION

The present invention relates to magnetic hard disk drives. Morespecifically, the present invention relates to electrical connectionsfor micro-actuators.

In the art today, different methods are utilized to improve recordingdensity of hard disk drives. FIG. 1 provides an illustration of atypical disk drive with a typical drive arm 102 configured to read fromand write to a magnetic hard disk 104. Typically, voice-coil motors(VCM) 106 are used for controlling a hard drive's arm 102 motion acrossa magnetic hard disk 106. Because of the inherent tolerance (dynamicplay) that exists in the placement of a recording head 108 by a VCM 106alone, micro-actuators 110 are now being utilized to ‘fine-tune’ head108 placement. A VCM 106 is utilized for course adjustment and themicro-actuator 110 then corrects the placement on a much smaller scaleto compensate for the VCM's 106 (with the arm 102) tolerance. Thisenables a smaller recordable track width, increasing the ‘tracks perinch’ (TPI) value of the hard drive (increased drive density).

FIG. 2 provides an illustration of a micro-actuator as used in the art.Typically, a slider 202 (containing a read/write magnetic head; notshown) is utilized for maintaining a prescribed flying height above thedisk surface 104 (See FIG. 1). Micro-actuators may have flexible beams204 connecting a support device 206 to a slider containment unit 208enabling slider 202 motion independent of the drive arm 102 (See FIG.1). An electromagnetic assembly or an electromagnetic/ferromagneticassembly (not shown) may be utilized to provide minute adjustments inorientation/location of the slider/head 202 with respect to the arm 102(See FIG. 1).

The electric trace connection connecting the micro-actuator to theprinted circuit assembly currently passes over the suspension assembly,or suspension tongue. This design results in an increased stiffness inthe suspension assembly due to the electric trace connection. Further,micro-actuator bonding, using methods such as gold ball bonding orsolder bump bonding, is difficult as the bonding pad is located on themicro-actuator moving beam. Not enough support space exists to connectthe micro-actuator. Also, the bonding process can damage themicro-actuator beam due to pressure or bonding force. The lowerstiffness of the electric traces also makes it easier to deform thetrace connection.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 provides an illustration of an internal view of a hard disk driveincluding a drive arm configured to read from and write to a magnetichard disk as used in the art.

FIG. 2 provides an illustration of a micro-actuator as used in the art.

FIGS. 3 a-b describes a hard disk drive head gimbal assembly (HGA) witha ‘U’-shaped micro-actuator under principles of the present invention.

FIGS. 4 a-d provide an illustration of one embodiment of amicro-actuator with the electric arm contact pads situated near the basepiece of the micro-actuators.

FIGS. 5 a-c provide an illustration of one embodiment of the componentsof a head gimbal assembly and a micro-actuator with the electric armcontact pads situated away from the base piece of the micro-actuator.

FIG. 6 provides an illustration of one embodiment of an assembled headgimbal assembly micro-actuator with the electric arm contact padssituated away from the base piece of the micro-actuator.

DETAILED DESCRIPTION

A suspension design for a micro-actuator that reduces suspension tonguestiffness and a method of manufacturing the HGA with the micro-actuatorare disclosed. In one embodiment, the micro-actuator has a base piecewith two arms extending from the base piece. The electric contact padsfor the arms are situated on the exterior of the arms at the endopposite the base piece. In one embodiment, the electric contact padsare electrically coupled to the same connection plate as the magneticread/write head. This design provides enough support space for theelectric coupling of the micro-actuator as well as the magneticread/write head, preventing the damage caused during the bondingprocess. The electric connection traces for the micro-actuator areconsolidated with the traces for the magnetic read/write head on theoutriggers of the suspension tongue, reducing the stiffness of thetongue itself.

Illustrated in an upside-down orientation, FIG. 3 a describes oneembodiment of a hard disk drive head gimbal assembly (HGA) with a‘U’-shaped micro-actuator. In one embodiment, a magnetic read/write head302, or slider, is coupled to a ‘U’-shaped micro-actuator 304. In afurther embodiment, the ‘U’-shaped micro-actuator has a piezoelectricLead Zirconate Titanate (PZT) beam (arm) 306 extending from each side ofa base piece 308. In another embodiment, the ‘U’ shaped micro-actuatorbase piece 308 is attached to the suspension tongue 310 of an HGA 312 bypartial potting. The tongue creates a parallel gap between thesuspension tongue and the bottom of the PZT beam 306 and the bottomsurface of the slider 302. In one embodiment, the parallel gap is 25 μmto 50 μm. In one embodiment, a printed circuit assembly 314 iselectrically coupled to the slider 302 to control reading and writingfunctions. A pair of outriggers 316, each with a bend 318, supports thesuspension tongue 310 and maintains the parallel gap between thesuspension tongue 310 and a loadbeam 320. In one embodiment, the bendingheight is 50 μm. A first hole 322 is cut into the HGA 312 to reduceweight. A second hole 324 allows the HGA 312 to be mounted on a pivot.FIG. 3 b illustrates the present embodiment in a reverse orientation.

FIGS. 4 a-d illustrate an embodiment of a micro-actuator 302incorporated into a known HGA 312 (e.g., such as the one described inJapanese Patent 2002-133803). FIG. 4 a shows one embodiment of aconnection plate 402. In one embodiment, the connection plate has a setof electric head plate contact pads 404 attached to the connection plate402. In a further embodiment, the set of electric head plate contactpads 404 includes read electric plate contact pads and write electricplate contact pads. In one embodiment, a first set of one or moreconnection traces 406 connects the set of electric head plate contactpads 404 with the printed circuit assembly 314. FIG. 4 b shows a toptrailing edge view of one embodiment of the head 302 coupled to themicro-actuator 304 and the connection plate 402. The head 302 iselectrically coupled to the electric head plate contact pads 404. In oneembodiment, the head is electrically coupled by solder bump bonding orgold ball bonding. A set of electric arm contact pads 408 is attached tothe suspension assembly 310. A second set of one or more connectiontraces 410 connects the set of electric arm contact pads 408 to theprinted circuit assembly 314. The connection traces 406 for the electrichead plate contact pads are exposed and subject to deformation. FIG. 4 cshows a top leading edge view of one embodiment of the head 302 coupledto the micro-actuator 304 and connection plate 402. FIG. 4 d shows abottom view of one embodiment, of the loadbeam 320 and suspension tongue310. Only a small amount of support space 412 is available for theelectric bonding of the micro-actuator, making the micro-actuatorsusceptible to damage.

FIGS. 5 a-c illustrate the components of one embodiment of the presentinvention. FIG. 5 a illustrates one embodiment of a connection plate402. In one embodiment, the connection plate 402 has a set of electrichead plate contact pads 404 and a set of electric arm plate contact pads502 attached to the connection plate 402. In one embodiment, a first setof one or more separated connection traces 504 connects a first set ofelectric head plate contact pads 404 and a first set of electric armplate contact pads 502 with the printed circuit assembly 314. In analternate embodiment, a second set of separated connection traces 506connects a second set of electric head plate contact pads 404 and asecond set of electric arm plate contact pads 502 with the printedcircuit assembly 314. In one embodiment, the left electric arm platecontact pads 502 and the right electric arm plate contact pads may beinterconnected.

FIG. 5 b illustrates one embodiment of a micro-actuator 304 and magneticread/write head 302. In one embodiment, the magnetic read/write head iscoupled between the two arms 306 of the micro-actuator 304. In a furtherembodiment, a set of one or more electric arm contact pads 508 isattached to the exterior of each arm 306 at the end opposite the basepiece 308.

FIG. 5 c illustrates one embodiment of a suspension tongue 310. Theconnection plate 402 is inserted between the loadbeam 320 and twolimiters 510. In one embodiment, a first set of one or more connectiontraces 504 and a second set of one or more connection traces 506 linkthe connection plate 402 to the printed circuit assembly 314 via the HGA312. The first set of separated connection traces 504 and the second setof separated connection traces 506 have increased stiffness as theyinclude the connection traces for the magnetic read/write head 302 andthe micro-actuator 308.

FIG. 6 illustrates one embodiment of the micro-actuator 304 assembledwith the connection plate 402 and the HGA 312. The base piece 308 of themicro-actuator 304 is affixed to the suspension assembly 310 of the HGA312. In one embodiment, the base piece 308 is coupled to the suspensionassembly 310 by partial potting. In one embodiment, the magneticread/write head 302 is situated between the arms 306 of themicro-actuator 304. In one embodiment, the magnetic read/write head 302is electrically coupled to the electric head plate contact pads 404attached to the connection plate 402. In a further embodiment, the setof electric arm contact pads 508 attached to the arms 306 ofmicro-actuator is electrically coupled to the set of electric arm platecontact pads 502 attached to the connection plate 402. This couplingallows the printed circuit assembly 314 to control the movement of themicro-actuator arms 306. In a further embodiment, the electric arm platecontact pads 502 and the electric head plate contact pads 404 of theconnection plate 402 supply enough space to support the boding of boththe head 302 and the micro-actuator 304.

Although several embodiments are specifically illustrated and describedherein, it will be appreciated that modifications and variations of thepresent invention are covered by the above teachings and within thepurview of the appended claims without departing from the spirit andintended scope of the invention set of electric arm plate contact pads.

1-12. (canceled)
 13. A method, comprising: manufacturing amicro-actuator with a first piezoelectric arm coupled at a first end toa base piece and a second piezoelectric arm coupled at a first end tothe base piece; attaching a first electric arm contact pad to the firstpiezoelectric arm at a second end opposite to the base piece; andattaching a second electric arm contact pad to the second piezoelectricarm at a second end opposite to the base piece.
 14. The method of claim13, further comprising coupling the micro-actuator to a suspensionassembly of the head gimbal assembly.
 15. The method of claim 14,wherein the micro-actuator is coupled at the base piece to thesuspension assembly by partial potting.
 16. The method of claim 14;further comprising maintaining a parallel gap between the suspensionassembly and a bottom surface of the magnetic read/write head and themicro-actuator.
 17. The method of claim 13, further comprising:attaching one or more first extra electric arm contact pads to the firstpiezoelectric arm at a second end opposite to the base piece; andattaching one or more second extra electric arm contact pads to thesecond piezoelectric arm at a second end opposite to the base piece. 18.The method of claim 13, further comprising: attaching a first and asecond set of electric head plate contact pads to a connection plate;electrically coupling the first and second set of electric head platecontact pads to the magnetic read/write head; attaching a first and asecond set of electric arm plate contact pads to the connection plate;and electrically coupling the first and second set of electric arm platecontact pads to the first and second electric arm contact pads.
 19. Themethod of claim 18, further comprising connecting the first set ofelectric head plate contact pads and the first set of electric arm platecontact pads to a printed circuit assembly with a first set ofelectrical connection traces.
 20. The method of claim 18, furthercomprising connecting the second set of electric head plate contact padsand the second set of electric arm plate contact pads to a printedcircuit assembly with a second set of electrical connection traces. 21.The method of claim 18, wherein the first and second set of electrichead plate contact pads each include a set of read electric head platecontact pads and a set of write electric head plate contact pads. 22-25.(canceled)